The main difference is an arrow with a quality razor sharp broadhead kills by massive blood loss.
A well placed broadhead whether shot by an 80# draw weight or a 50# draw weight bow will cut enough vital vessels or organs to cause a quick death to the animal.
Bullets are similar but used hydrostatic shock travelling through the juicy parts of the body to cause massive damage to the bodies vital organs.
A properly tuned 50 pound draw weight bow will shoot an arrow through a 5 gallon bucket of sand as where a 30-06 shooting a hunting type bullet won't travel all the way through the bucket.
Which one killed the bucket deader?
I shot big bows from 1976 to 2004. I always shot heavy thick walled aluminum arrows because I could handle the stress placed on my frame at the time. If the big heavy weight bows turn your screw, have at them. Learn the hows and whys an arrow works and it is obvious that in todays age and technology, a big heavy draw weight bow is just not necessary.
I am not telling the world that shooting big bows is stupid. Do it if that is what makes you confident and lethal, What I am saying is that 80 to 100 pound draw weights really do nothing for you that a well tuned 55 pound draw weight bow can't do.
You are the one doing the shooting. Do what you want. I did the big bows for a long time and I feel that all the joint problems that I have on my upper body are from muscling back big bows. I could have done the same amount of blood letting with two-thirds of the power.
ETA I did not realize this thread is so old. The information is the same though. Sorry.